Détails:A Learjet 35A corporate jet, registered N800GP, sustained substantial damage in a landing accident at Springfield-Abraham Lincoln Capital Airport, IL (SPI), USA. All four passengers and two crew members survived. The airplane operated on Priester Aviation flight 800 from Chicago-Midway Airport, IL (MDW) to Springfield-Abraham Lincoln Capital Airport, IL (SPI).The en route and descent part of the flight were uneventful. The airplane accumulated a trace of rime ice during the descent and approach. The airframe anti-icing system was turned off upon intercepting the ILS glide slope, which was shortly before descending below the cloud layer. The copilot was the pilot flying at the time of the accident. He used the autopilot for the initial portion of the approach and then hand flew the airplane after breaking out of the clouds. The pilot stated that the master warning and stick shaker activated when the airplane was on short final. The airplane impacted left of the runway centerline before it ultimately departed the right side of the runway pavement. The airplane crossed a slight rise before coming to rest in the grass. A small fire was quickly put out by military staff, both pilots received minor back injuries, and there were no injuries among the four passengers.

PROBABLE CAUSE: "The pilot’s decision to conduct an instrument approach in icing conditions without the anti-ice system activated, contrary to the airplane flight manual guidance, which resulted in an inadvertent aerodynamic stall due to an in-flight accumulation of airframe icing."